As is well known, to ensure a continuous supply of ink from a reservoir (or refill) inside the said hollow barrel, connected to the nib, air must be allowed to enter this barrel from the outside so that the gradual outflow of ink during writing does not result in a vacuum that would prevent that outflow. In the prior art this is achieved by making a hole through the wall of the hollow barrel, or making the above-described hole at the lower end of the barrel slightly larger than the part of the stem housed within it, in order to create a clearance which will leave a large enough gap for air to enter.
While the first approach raises aesthetic problems which may be incompatible with the quality image of ballpoint pens of a certain value, the second approach is detrimental both to the precision of the writing action (the nib tends to move inside the hole while writing) and the impression of careful workmanship and sturdiness and reliability of the ballpoint pen which a user may perceive.
Another problem relating to the manufacture of ballpoint pens is how to cool the nibs as quickly as possible while they are being stamped, sized, drilled etc.
Because of the fast production rates demanded in the processing of nibs for ballpoint pens, which are details with low added value, even a very small lengthening of the processing cycle time of each individual nib has significant repercussions on production costs.